A typical apparatus for dry-forming a fibrous sheet is disclosed in U.S. Pat. No. 3,862,472, issued to Henry J. Norton, et al., assigned to the assignee of this invention. In Norton, et al., the fibrous web is formed on a foraminous endless conveyor. As disclosed in U.S. Pat. No. 4,207,367, issued to John H. Baker, Jr., assigned to the assignee of the subject invention, the dry-formed web of the Norton, et al. patent is transferred to a conveyor that transports the web to a spray station where the web is moistened. The moistened web is then removed from the spray conveyor and passed through an embossing nip. In the prior art, as represented by U.S. Pat. No. 4,207,367, the formed fibrous sheet is not supported as it is transferred from the forming conveyor onto the spray conveyor. As those skilled in the art would say, the web travels over an "open draw". Also, in the prior art, as represented by the U.S. Pat. No. 4,207,367, the transfer of the web from the spray conveyor into the embossing nip is made over an open draw. One of the major problems in trying to increase the speed of manufacturing such an embossed, dry-formed web is that because the web does not have great strength, it will quite often break at the open draw into the embossing nip. It has further been found that if the embossing speed is increased by conveying the web through the embossing nip, further speed increases are limited by the increased tendency for the web to break at the open draw to the spray conveyor.
U.S. Pat. No. 389,949, issued to J. M. Baker, describes an embossing machine in which an embossing roll B forms an embossing nip with an anvil roll D which can have a resilient surface. As stated at lines 52-55, an endless, non-porous elastic belt, L, of soft rubber or other appropriate material is passed over pulleys KK and the roller D so as to pass through the embossing nip. As further stated at lines 89-93, the material to be embossed rides on the belt L as it passes under the embossing roll B.
U.S. Pat. No. 4,038,917, issued to John DeLigt, also discloses embossing a web while it is on a non-porous, resilient film as it passes through an embossing nip formed by an embossing roll and an anvil roll.
There are several problems with embossing web dry-formed on a non-porous, elastic belt as described in the prior art patents to J. M. Baker and John DeLigt. When the dry-formed web and the belt enter the embossing nip at high speeds, the embossing roll begins to squeeze the air within the web out of the web. Since the belt is non-porous, the air being squeezed out of the web cannot pass through the belt so it lifts the web from the belt to form a pocket or a bubble from which air escapes through the web. A further problem with an elastic belt, such as the rubber belt of J. M. Baker or the resilient belt of DeLigt, is that any forces on the belt in the vicinity of the embossing nip which cause stretching of the belt in either the cross or machine direction will result in forces exerted on the web in the cross and machine directions, which in the case of weak, dry-formed webs, acts to separate fibers in the web which tends to fracture the web.
It is one object of this invention to eliminate the open draw transfer of a dry-formed web into an embossing nip at relatively high speeds.
Another object of the invention is to provide apparatus for assisting the transfer of a dry-formed web over the open draw between a first conveyor and a second conveyor.